Smoke retardant compositions

ABSTRACT

Iron oxide admixed with copper or molybdenum compounds, impart smoke retardant properties to combustible materials such as plastics. Thus for example, polyvinyl chloride does not emit as much smoke during combustion when it is compounded with Fe2O3, MoO3, and Cu2O.

260/45.75 P, 31.8 R, 23 XA United States Patent H [H1 3,903,028

Mitchell Sept. 2, 1975 SMOKE RETARDANT COMPOSITIONS [75] Inventor: Lawrence C. Mitchell, Mt. Vernon. [56] References Cited UNITED STATES PATENTS Assignee: Corporation Richrnond VZL 2.286.744 Lcathermzm l 7 l Ffled' lune 1974 Primary I:'.\'umim"rV. P. Hoke [2]] Appl. No.: 477,437 Allorney. Agent, or Firm-Donald L. Johnson; Robert Related U.S. Application Data Lmn [63] Continuation-impart of Scr. No. 355,652. April 30. 1973, abandoned. which is u continuation-in-purl of [57] ABSTRACI Ser. NO. 196,80], NOV. 8. 1971, Put. NO. 3.845.0Ul. Iron xide admixed c ppcr or molybdenum compounds. impart smoke retardant properties to combusl l (1360/23 2 260/45-75 2 tible materials such as plastics. Thus for example. pol- /4575 R; 260/4575 260/4575 G; yvinyl chloride does not cmit as much smoke during 260/45-75 260/4575 N combustion when it is compounded with Fe O M00 1 Int. Cland Cu ,0 [58] Field of Search 260/4575 C. 45.75 R.

6 Claims, N0 Drawings SMOKE RE'I'ARDANT COMPOSITIONS This application is a continuation-in-part ofapplication. Ser. No. 355.652. filed Apr. 30. I073. and now abandoned. which in turn is a continuation-in-part of application Ser. No. 19 .801. filed Ni. 8. W71. and now US. Pat. No. 3.845.001.

BACKGROUND OF THE INVENTION This invention provides additives for plastics that will decrease their tendency to smoke when burned. It is believed that such use of the additives provided has not been described in the art.

Netherlands patent No. 69/18,86l is reported to teach that preparations of antimony trioxide and an inorganic salt impart flame and smoke reducing properties to resin compositions.

Iron oxide and other oxides have been added to polyvinyl halide for pigment purposes; Woernle. SPE Journal. pages 535-544 (May I960): DeCaste and Hansen. Ibid. 18 No. 4 pp 43l439 (April 1962).

SUMMARi OF THE INVENTION In one aspect. this invention provides a polyvinyl halide admixed with a smoke retardant amount of iron oxide. In another aspect. this invention provides polyvinyl halide compounded with a mixture of iron oxide with copper oxide and/or molybdenum oxide.

This invention also provides a method for imparting smoke retardancy to plastics which method comprises blending resins with compounds such as set forth above. Similarly, this invention provides blends for incorporation in resins. Such blends may be mixtures of the compounds themselves or the compound mixtures can be combined with the resin or other materials such as a solvent. or a plasticizer or other ingredient utilized to form a resin composition.

Smokes can be a hazard during a fire. Dense smoke hampers fire fighting measures and can obscure escape routes for those within a burning enclosure. Therefore. building materials which emit lesser amounts of smoke during combustion can be a safety feature. This invention serves to provide compositions with lessened tendencies to smoke and accordingly. one utility of this invention pertains to improvement in materials utilized in construction. However. formulations of this invention can be used wherever it is desirable to use materials which can lessen the amount of smoke produced upon combustion.

DESCRIPTION OF PREFERRED EMBODIMENTS In the practice of this invention, a smoke retardant amount of additive is used to treat a combustible material such as a plastic resin.

Polyvinyl halide resins can be used in this invention. Applicable polyvinyl halides include homopolymers. copolymers and polymer mixtures. Illustrative and nonlimiting examples of applicable polyvinyl halide resins are:

l. Homopolymers Polyvinyl chloride. polyvinyl bromide. polyvinyl fluoride. polyvinylidenc chloride. polydichlorostyrene and the like,

2. Copolymers Vinylchloride-vinyl acetate. vinylchloridc-vinyl alcohol. vinylchloride-vinylidenc chloride. vinylchloride-diethyl maleate. vinyl chloride esters of unsaturated alcohols and unsaturated acids and the like. and

r 3. Mixtures Polyvinyl chloride and polydichlorostyrene. polyvinyl chloride and vinyl acetate-vinyl chloride copolymer. polyvinyl chloride. polyvinylidene chloride. and a ,copolymer of vinyl vchloridediethylmalcate and the like. I 1

The resins can he treated with the smoke. retardant additive or additives in any convenient manner. In some instances. smoke retardancy may be achieved by treating one or more surfaces of a plastic article with the additive or additives such that it treated surface is overlayed or paddedwith the additive composition. However. in general. it is preferred to blend an additive within a resin composition. The blending can be accomplished by any appropriate blending or mixing technique available in the art. I I

In the practice of this invention. a smoke retardant amount of provided additive is used to treat a combus tible substance. In general. there is usually a relationship between the smoke retardancy achievable and the amount of additive employed. Therefore at least within some concentration range. usually a greater amountof additive will provide a greater amount of smoke retardancy. all other factors remaining the same. In some instances. there is a practical upper limit on theamount of additive used. This upper limit is based on secondary factors such as cost. ease of blending. or interference with some other desirable property of the substrate. for example. In many instances. from about 0.5 to about 40 parts by weight aroused for each [00 parts by weight of substrate resin. Preferably from about 1 to about 30 parts for 100 parts resin. more preferably 1 to about 15 parts per 100 parts resin are employed. However. greater or lesser amounts can be used if desired.

Ferric oxide. I e- 05;. can be used in this invention. Its use suggests utility of other iron oxides; viz. FeO and F8304.

For this invention a smoke retardant amount of an additive mixture is added to a polyvinyl halide as d'e-' scribed above. For binary mixtures such as iron oxidecopper compound or iron oxide-molybdenum corripound there can be from I to 99 parts by weight of the first substance to 99 to 1 parts by weight of the second. For example. within this range an exemplary additive mixture is cuprous oxide-ferric oxide (60:40). The numbers in parenthesis refer to parts by weight. Thus. this mixture contains 60 parts of Cu O and 40 parts of Fe O In this ternary mixture of iron oxide with a copper and a molybdenum compound each component can have from I to 98 parts by weight. Thus. the mixtures can be A. B. C. (1:1:98)

A. C, B. (l:98:1)

A. B. C. (98:1:1) where A signifies iron oxide. B a copper compound, and C a molybdenum compound. An exemplary ternary mixture of this invention is ferric oxideQ molybdenum trioxide-cuprous oxide (20:40:40). wherein the numbers in the parenthesis refer to parts by weight as referred to above. V

Cuprous or cupric oxide can be used. Cuprous oxide has been shown to give a better response insome testing. hence it is preferred. The applicability of such ox-' ides suggests the use of other copper'compounds such as the corresponding'sulfides. Cu(l) and Cu(II) chelates such as the acetonylacetates. copper salts of carboxylic' acids such as the acetates and butyrates. hy-

drates of all these. and organocopper compounds such as the copper carbonyls.

Molybdenum trioxide. M can be used in this iiivention. Also it has been found that molybdenum carless smoke Flexible PVC of the above mixture with 33 weight precent DOP without some suppressant had an SODc of 702, while a bonyl and ammonium paramolybdate reduce smoke. i. cuprous oxide-ferric oxide mixture (60:40) had an These may be admixed with the copper oxides. for ex- SODe of 468. and ample. ii. molybdenum trioxide cuprous oxide-ferric Applicability of such compounds suggests other moid 4 ;4 ;2 had 2m SODC f 475 lybdenum compounds can be blended; for example. ox- In (i) and (ii) the additive mixture was 4 parts by K1 n sulfides -z- 2 1 2. 1 weight per hundred parts by weight resin. lron oxide MoS MoS M0 5 metal molybdates such as ammoalone in the same concentration had an SODc of 770. mum and pp mvlyhdmcammonium 11nd sodlum Similar smoke reductions are obtained with flexible paramolybdate. molybdenum salts of carboxylic acids PVC i h wt percent DOP si il results are bsuehas acetates and butyrates. chelates such as the mi d using FQO or F o acetylacetonates and organomolybdenum compounds. 15 Si il results are b i d whcn Additional suggested molybdenum compounds are as iron oxide cuprous oxide or follows: iron oxide molybdenum trioxidc Table 1 mixtures in which the amount of each component is said mixture is from to 75 parts by weight.

a I 5 I 3 i 1 I I x 3 x 4 Dimeric ammonium 5-inolybdoeohaltate (lll) J) obtllntd Wht'n FLZOI" M003 tNH.) ;[('o M ,I'XH O (X= l0) Cu. .O mixtures are used wherein the amount of each Ammonium o-mi\lybdoeobaltate (Ill) n (NHM(MWONH'JXHBO oxide n said mixture is from about 10 to about 80 parts Ammonium bniolybdonickelate (IV) y g il -H. ..lN w- :wl" Similar results are obtained when the concentration Ammonium o-mtilybdoniekelate (H) tNH, .1Nilwo o u -x o of smoke retardant is 0.5 to parts by weight per hun- Aminoniuni h-mol \hdoaluniinate (lll) drcd parts by weight resin .illAIMUGo HUI-XHJ) ix-4-7i l I b y Ammonium o-molyhdochminute (Ill) resu ts 0 tamed when the cuprous Oxide 1NH.til rM n fl fil' flg in the above mixtures 18 replaced with cupric oxide or Ammonium o-molyluloferrate (Ill) th i l, d h h d MHA'XHJ) (X=5l0) m cse oxi cs are rep ace wit ot er compoun s such Mol \'bdcn \l iieei iiiet-iumiic as the corresponding sulfides. cyanides, Cu(l) and Cu(ll) chelates such as the formates, acetates, buty Example PVC Formulas:

Rigid 20 wt. /1 DOP 33 wt. DOP

Ethyl PVC 500 natural I00 parts Ethyl PVC SM-250 100 parts l00 parts Dioetyl phthalate (DOP) 30 parts parts Mark WS (Stabilizer) 1.0 parts l.0 parts Stearie acid (Lubricanl) 0.5 parts 0.5 parts Smoke retardant As indicated As indicated As indicated olyvinyl chloride "di-isooctylphthalale The smoke retardants were mixed by hand with the mtoxulatcs and the hydndes of all these and appropriate substrate and then mixed by Waring Blenf h compounds h the pp carbohyl5- 9 dor, Brabender Plastograph. or plastic mill. The homo- 51mm" results are Obhhhed h the molybhehum geneous mixture was molded in a heated press under so Oxide m the above Fixamples replace? Wlth MOO-H pressure. The resulting sheet was conditioned in an air 2 these oxldes are replaced Wlth the correcirculatcd oven at C overnight and at 73F and 50 spohchhg Shh-fies or other molybdenum compouhds percent relative humidity Overnight. such as ammonium and copper molybdate, ammonium paramolybdate, copper paramolybdate, molybdenum S CHAMBER g; salts of carcoxylic acids, such as acetates and butyrates, AMINCO NB chelates such as the acetylacetonates and the or- Specimens 3 inches X 3 inches square and 50 mil ganomolybdenum compounds such as molybdenum thick were cut. The conditioned specimen was placed hexacarbonyl. Likewise, similar results are obtained on aluminum foil cut to size to permit overlapping of when the molybdenum compounds in the mixtures are the specimen face on all four sides. The wrapped Speci- 60 replaced with those molybdenum compounds listed in men was placed in a holder and burned in the Aminco Table 1 above. NBS smoke chamber according to the directions sup- This invention may be extended to smoke retardant plied. The amount of smoke was measured by a photomaterial wherein the molybdenum is in a complex salt multiplier. Specific optical density was calculated and f id h as tho e found on pages 526-535 of F rir: corrected for soot remaining on the lends at the end of 6s Ephraim, Inorganic C/ILHH'SN'). 6th Edition by P. C. L.

the test. The average of two values is reported.

Rigid PVC as above, without a smoke suppressant gave a corrected optical density (SODc) of 554. In comparison, Fe. ,O at a 1 percent concentration had an SODc of 345. (In this test. the smaller the number. the

Thorne and E. R. Roberts, Interscience Publishers Inc.. New York, N.Y.; 1954. Exemplary salts of this type are ammonium 5-molybdocobaltate (III 9- molybdonickelate (lV). o-molybdoaluminate (Ill) and o-molybdochromate lll When using iron oxide admixed with copper and/or molybdenum compound in a flexible polyvinyl halide. it is preferred that the composition have -30 or more parts of plasticizer per 100 parts resin (parts are by weight). The plasticizer can be DOP. or the other materials mentioned in column a line 61 column 7. line 17 of US. Pat. No. 3.338.845.

I claim:

1. In a composition consisting essentially of a plasticized polyvinyl halide resin with a stabilizer and lubricant. the improvement comprising addition of from about 0.5 to about parts by weight per hundred parts by weight polyvinyl halide resin of a smoke retardant additive mixutre consisting essentially ofiron oxide and molybdenum oxide wherein the amount of each oxide in said mixture is from 2575 parts by weight.

2. In a composition consisting essentially of a plasticized polyvinyl halide resin with a stabilizer and lubricant. the improvement comprising addition of from about ()5 to about 40 parts by weight per hundred parts by weight polyvinyl halide resin of a smoke retardant additive mixture consisting essentially of F0 0 Cuand MoO wherein the amount of each oxide in said mixture is from about l0 to about parts by Weight.

3. The composition of claim 1 wherein said iron oxide is Fe o 4. A composition of claim 1 wherein said molybdenum oxide is MoO 5. A polyvinyl chloride of claim 2 wherein the amount of each oxide in said mixture is from about 20 to about 40 parts by weight.

6. The composition of claim 1 wherein said polyvinyl halide is polyvinyl chloride. I 

1. IN A COMPOSITION CONSISTING ESSENTIALLY OF PLASTICIZED POLYVINYL HALIDE RESIN WITH A STABILIZER AND LUBRICANT, THE IMPROVEMENT COMPRISING ADDITION OF FROM ABOUT 0.5 TO ABOUT 40 PARTS BY WEIGHT PER HUNDRED PARTS BY WEIGHT POLYVINYL HALIDE RESIN OF A SMOKE RETARDANT ADDITIVE MIXTURE CONSISTING ESSENTIALLY OF IRON OXIDE AND MOLYBDENUM OXIDE WHEREIN THE AMOUNT OF EACH OXIDE IN SAID MIXTURE IS FROM 25-75 PARTS BY WEIGHT.
 2. In a composition consisting essentially of a plasticized polyvinyl halide resin with a stabilizer and lubricant, the improvement comprising addition of from about 0.5 to about 40 parts by weight per hundred parts by weight polyvinyl halide resin of a smoke retardant additive mixture consisting essentially of Fe2O3, Cu2O, and MoO3 wherein the amount of each oxide in said mixture is from about 10 to about 80 parts by weight.
 3. The composition of claim 1 wherein said iron oxide is Fe2O3.
 4. A composition of claim 1 wherein said molybdenum oxide is MoO3.
 5. A polyvinyl chloride of claim 2 wherein the amount of each oxide in said mixture is from about 20 to about 40 parts by weight.
 6. The composition of claim 1 wherein said polyvinyl halide is polyvinyl chloride. 